1. Field of the Invention
The present invention relates to a method of production, method of inspection, and method of use of a scanning probe microscope probe provided with a sharp head made of a single wall carbon nanotube (SWCNT).
2. Description of the Related Art
A scanning probe microscope (SPM) is a microscope which observes the surface of a sample by scanning by a probe having a sharp tip. It does not require a vacuum like an electron microscope such as an atomic force microscope (AFM) and enables observation of the surface of materials on the nanometer order in various environments (gases and liquids). Therefore, it is becoming an important tool for the development of various new materials such as bio related materials, catalyst materials, and semiconductor materials.
The dimensions of the tip of the probe are directly related to the resolution, so the tip is made from silicon (Si) or silicon nitride (Si3N4) able to be microprocessed by a semiconductor process. Even so, even at the sharpest, the radius of the tip is about 5 nm. In general, it is over 10 nm. Further, the open angle of the tip is several tens of degrees or more, so deep relief patterns on the sample surface cannot be faithfully reproduced.
Therefore, to obtain a higher resolution, Japanese Unexamined Patent Publication (Kokai) No. 2000-227435 (paragraphs [0042] to [0043]) proposes to use a carbon nanotube (CNT) as the probe.
A carbon nanotube has superior features as a probe such as 1) a small radius of the tip (radius of as small as about 1 nm) and therefore a higher possible resolution in the horizontal direction, 2) a large possible aspect ratio and therefore the ability to faithfully reproduce deep relief patterns, and 3) a higher elasticity compared with conventional probe materials such as silicon and silicon nitride and therefore no damage even if striking the sample, a greater durability, and a longer service life.
In the proposal of Japanese Unexamined Patent Publication (Kokai) No. 2000-227435, a multiwall carbon nanotube (MWCNT) fabricated in advance is attached to the tip of a probe body and secured by a carbon film under observation under a scan electron microscope so as to fabricate a scanning probe microscope probe provided with a sharp head made of a multiwall carbon nanotube.
Since an attachment operation under observation by a scan electron microscope was required, from the viewpoint of the observability and handling strength, application of the above proposal required a carbon nanotube of a size of a diameter on the order of 10 nm (FIG. 1A). Therefore, while application to a multiwall carbon nanotube was possible, application to a single wall carbon nanotube (SWCNT) having a diameter of 1 nm or less (FIG. 1B) was not.